γ-Al2O3-Supported PtRu Clusters Prepared from [Pt2Ru4(CO)18]: Characterization by Infrared and Extended X-ray Absorption Fine Structure Spectroscopies
| Autor: | Bruce C. Gates, Oleg S. Alexeev, Mordecai Shelef, and Richard D. Adams, George W. Graham |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry B. 106:4697-4704 |
| ISSN: | 1520-5207 1520-6106 |
| Popis: | Highly dispersed γ-Al2O3-supported PtRu clusters were prepared by decarbonylation of molecularly adsorbed [Pt2Ru4(CO)18] in He or H2 at temperatures in the range of 300−400 °C. Infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies were used to characterize the supported species before and after removal of the CO ligands. The IR and EXAFS spectra show that most of the [Pt2Ru4(CO)18] interacted weakly through its CO ligands with the surface hydroxyl groups of γ-Al2O3 and could be extracted into CH2Cl2, but a small fraction of the [Pt2Ru4(CO)18] interacted strongly with the support and could not be extracted. The strongly bonded species, characterized by a νco band at 2063 cm-1, formed as a result of nucleophilic attack of some support hydroxyl groups on carbonyl ligands, leading to the removal of these ligands as CO2 and formation of covalent bonds between the clusters and the oxygen atoms of the support. The EXAFS data show that after decarbonylation in He or H2 at 300−400 °C, t... |
| Databáze: | OpenAIRE |
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